He was freed by a judge after a Michigan state police investigation in 2016. The city and the officers have declined comment on the lawsuit.

Davontae was 15 when he pleaded guilty to four murders and was imprisoned in 2008. He's 24 years old now. Sanford walked out of prison Wednesday, after a judge erased the guilty pleas at the request of Wayne County prosecutor Kym Worthy.

The case appeared closed and unremarkable until lawyers discovered a hit man's confession to the same killings -- along with eight other killings -- just 15 days after Sanford was sent to prison.

That touched off years of efforts to get the guilty pleas set aside, but prosecutors resisted at every turn until state police were asked last year to take a fresh look. The hit man's name is Vincent Smothers.

Wayne County Prosecutor Kym Worthy laid out the entire process of getting Davontae freed last year and pointed out the young man entered a guilty plea, even though he didn't do the crime.

"This wasn't a young man that made his decision to plead guilty in a vacuum. He was consistently offered a chance to speak with his family members and any other person he wanted to speak to before he made the decision to plead guilty," Worthy said.

But former journalist Bill Proctor who is founder of Proving Innocence which played a role getting him released, ripped into Worthy at the time.

"Kym Worthy did not mention today that in this long running explanation of process and procedure, there was no seeking of true justice," he said at the time. "It was just a matter of taking step one, to step two, to this judge, to this prosecutor, to this appeal. The real bottom line is she had the authority that she essentially did not use."

Davontae talked about staying focused while behind bars. He read, wrote, and got an education because he knew he would be freed someday. He says his goal now is to continue his education, focus on young people who are at risk, and has a message to anyone incarcerated: stay strong.